To get a proven, easy-to-follow strategy for giving your lawn the right amount of water, we talked to lawn care expert Matt Maurer, owner of , with branches in Cincinnati and Dayton, Ohio. Follow these eight tips for healthy grass with a deep, strong root system.
The absolute best time to water your lawn is the early morning, before 10AM, says Maurer. Cooler temperatures and calm breezes help keep evaporation to a minimum. And watering in the morning keeps the turf cooler during the hot parts of the day, which means less stress on the grass.
If you can't water in the morning, late afternoon is the next best time. It might seem smart to wait for evening's cooler temperatures, but watering then keeps lawns wet overnight, which can make your lawn susceptible to disease. "My pet peeve is when people water at six o'clock or later in the evening," Maurer says. "A wet lawn at night is the perfect condition for fungus to grow." Along with cutting the lawn too short, watering a lawn at night is about the worst thing you can do to it, he says.
Water long enough to moisten the soil about 6 inches down, which is the depth of a healthy grass root system. It takes about one inch of water to wet normal lawns to that depth.
But, says Maurer, "Each lawn has different soil. You have to water for your property." There are several easy ways to check whether your lawn is getting the right amount of water.
The easiest way is the screwdriver test: after watering, a long screwdriver blade should penetrate the soil easily to a depth of six inches. If it doesn't, you're not watering enough. You can also use a shovel to lift the sod, but the screwdriver test is easier on your lawn.
If you just bought a new sprinkler, do some flow-rate math. Multiply the square footage of your lawn by .62 gallons (the amount needed to reach one inch of water per square foot) and then divide by your sprinkler's flow rate to determine how long to water.
Don't know your sprinkler's flow rate? Just set out a can in the watering zone and time how long it takes to get to one inch deep.
Built-in lawn sprinklers are the best systems for watering the grass. "This is the most efficient system and will pay for itself in the long run," Maurer explains. "Over the years, if you're planning on staying in the house, it's worth the investment."
But for homeowners who don't have an in-ground irrigation system and don't want to invest in one, he says, a pulsating, revolving sprinkler hooked up to a garden hose is the next best choice for an established lawn (for a new lawn, see the next tip). The sprinkler shoots out the water horizontally at a high velocity so it's not as vulnerable to wind and evaporation as oscillating types, which spray the water straight up.
Pulsating sprinklers work great for lawns with mature grass, but for new yards, the intense water stream can wash away the seeds. Oscillating sprinklers are a better choice for new lawns until the grass takes root.
"Oscillating is good for new grass, for seed. The water is not too strong to push the seed. The water is softer when it lands," Maurer says.
For newly planted grass seed, keep the top inch of the soil most, but not soggy. Monitor and water regularly until it reaches a three-inch height, then water on your regular cycle.
If you've planted sod, water it 15 minutes a day (twice a day in very hot weather) for the first two weeks. You can walk the seams to gently press the sod into the soil and help the roots to knit.
Maurer recommends watering clay soils once a week and sandy soils about every three days. "People think they need to water the lawn like they water their landscape plants. They want to water for 15 minutes every day," he points out. "You don't want to over-water. Most people think more water is better. But it's not."
Frequent, light watering can lead to fungus and a shallow root system; fewer waterings that soak the soil more deeply encourage the roots to grow deeper. "You want to train the roots to go down deep into the soil," he says. "I'm telling my customers if you're going to water, water every three to seven days once we hit summer. Water deeply and water infrequently." If you see mushrooms sprouting in your lawn, that can be a sign you're watering too much.
If you're watching the clock and trying to remember to shut off the water on time, chances are that sometimes you'll sit down in front of the TV or let your mind wander and forget that the sprinklers are running. So get a timer. They start at about $10 at home centers and turn off the water automatically after a designated time to ensure the lawn gets the proper amount of water. The timer connects to the spigot, then the hose connects to the timer. "With a timer, you don't have to worry [if] you forget the lawn is being watered," Maurer says.
Some timers also measure flow rate, so you can get an accurate idea of exactly how much water your lawn needs to stay green and lush without overwatering.
If homeowners don't want to water their lawn, that's fine, Maurer says. The lawn can go dormant just like it does in the winter without harming the grass, providing there's not a drought longer than a month. But letting the lawn go dormant, then watering, and then discontinuing the watering again is hard on the grass.
"You don't want to half-water and go back and forth between dormant and watering. You stress-out the grass," Maurer says. A dormant lawn will come back to life after a good rainstorm. "The lawn will come back naturally, just like it does when it goes dormant in the winter."
Lawns in new housing developments where the topsoil was removed often have a soil so hard water won't sink in. In that case, homeowners need to water in stages to soften the ground so the water can work its way down. "Water for 30 minutes, let it soak in, then water for another 30 minutes," Maurer says. "If you do it all at once, after 30 minutes the water will run off."